The present invention relates, in general, to heating, ventilating and air conditioning (HVAC) systems, and more particularly to HVAC systems having variable-air-volume (VAV) diffusers or VAV boxes with adjustable temperature set point controllers.
The use of variable air volume (VAV) devices in order to control the temperature and/or ventilation in large buildings is wide spread. Such HVAC systems typically have at least one, and sometimes a plurality of VAV devices located in the various spaces, rooms or offices within the building for control of the discharge of conditioned air into the offices. The air will be provided by a central source, and the volume air discharged into each office within the building will be varied in accordance with the control mechanism for the VAV device. Such VAV devices typically have a damper or set of blades, which is moved by an actuator so as to change the area of the opening from which conditioned air is discharged from the VAV device. VAV boxes most often are positioned upstream of a plurality of passive (damperless) air diffusers, while VAV diffusers include actuators and dampers at the structure discharging air into the space or office.
The control assembly for a VAV device will have one or more temperature set points which are used as a basis for regulating opening and closing of the damper by the actuator so as to drive the room temperature toward the set point. One set point may be used, for example, when the system is in a heating mode, while another may be used for a cooling mode. In some systems, however, the same temperature set point is used for heating and cooling.
In large office buildings, the HVAC system will be coupled to a plurality of thermostats located in the various offices or to a central building HVAC computer for monitoring and adjusting the set points for the VAV devices. In multiple thermostat systems, wiring must be run between individual VAV devices and the thermostats. In central computer systems, the computer is coupled through an HVAC building computer network that is coupled to the VAV devices. The central building control computer, therefore, can be used to monitor and adjust the set point temperatures of the various actuators in the VAV devices for individual offices.
One of the major disadvantages of thermostat-based systems is the wiring required during installation, which can be tricky in open office environments having free-standing work stations and space-dividing partition systems. A major disadvantage of building-wide HVAC computer monitoring systems is that the temperature set point adjustments must be made from a central monitoring station. Thus, the occupants of the individual offices in the building are not able to provide direct input as to the desired temperature set point for the VAV device effecting their office. Instead, occupants typically communicate with the building central monitoring and adjustment computer by telephone so as to make their wishes known with respect to environmental demands in their office.
It would be highly desirable, therefore, to have an HVAC system suitable for large buildings in which the individual VAV devices are capable of having their temperature set point independently directly adjusted by occupants of the offices through a method other than using wall-mounted thermostats. Thus, the occupants, who know best what environmental conditions are most suited for their office at a given time, would like to have a way of adjusting the HVAC system for their space without having to communicate with, or go through, a central monitoring computer, and without having to go to a wall-mounted thermostat.
Accordingly, it is an object of the present invention to provide a process and apparatus for individual adjustment of the temperature set points of a VAV device located in an occupant""s office without affecting other offices and without using a thermostat or having to communicate by telephone to a person at a central computer.
It is a further object of the present invention to provide a means for the occupant of a space in the building to easily adjust the temperature set points of the VAV device discharging air into his or her space using computer equipment commonly available in an office environment, such as personal computers, local area or wide area network and network services.
It is still a further object of the present invention to provide a VAV device adjustment system which is easy to install, is user-friendly, is relatively low in cost and provides a wide range of user flexibility.
The process and apparatus of the present invention have other objects and features of advantage which will become more apparent from, and are set forth in more detail in, the following Description of the Best Mode of Carrying Out the Invention and the accompanying drawings.
A process for individual adjustment of the temperature set point of a plurality of VAV boxes in an HVAC system for a building is provided, which is comprised, briefly, of coupling a plurality of computers, located in a plurality of spaces or offices in the building for input of a temperature set point based signal which can be communicated, directly or through a network server, to the VAV device located for the discharge of air into each space in which the computer is located. The temperature set point based signal can be a signal from a computer input device which is directly communicated, using a wired or wireless coupling, to the VAV device, or it can be a signal which is input to a network server device and thereafter is used to control the VAV device. Each VAV device is responsive to the temperature set point based signal to adjust the temperature set point for the VAV device in the space of the selected computer. The method includes further the steps of inputting a temperature set point from a selected computer for adjustment of the VAV device located in the same space; and communicating a temperature set point based signal from the selected computer to the VAV device by using one of a direct coupling and encoded signals through a network server to effect adjustment of the temperature set point independently of other VAV devices in the HVAC system.
The HVAC system of the present invention comprises, briefly, a plurality of VAV devices each adapted for receipt of a signal to adjust a temperature set point for operation of the VAV device, at least one of the VAV devices being located in each of a plurality of spaces in a building, and a plurality of computers each adapted to produce signals suitable for adjusting the temperature set point of a VAV device and being located in the plurality of spaces having the VAV devices therein. The plurality of computers each further are directly or indirectly coupled and adapted for the transmission of a signal to the VAV device located in the same space so as to adjust the temperature set point of the VAV device.
In the most preferred form, a desktop, laptop or other multipurpose computer of the type commonly employed in business, government and educational applications is coupled through a first computer network to the network server, and the network server is coupled to a second network which is connected to each of the VAV devices. Temperature set point based signals can be stored periodically in the server, retrieved and communicated as temperature set point based encoded signals on the second network to the VAV devices so as to enable adjustment of the VAV device temperature set point in the office or space having input the server. Optionally a building control computer can be coupled to the server or the second network.